Central Neural System

The central neural system is made up of the brain and the spinal cord, and the brain is its most important part. The brain is the central information-processing organ of the body and works as its command and control system. Almost every activity that keeps the body running and every higher function of the mind is coordinated here.

The brain looks after a wide range of tasks, including:

• Controlling voluntary movements of the body.
• Maintaining the balance of the body.
• Regulating the working of vital involuntary organs such as the lungs, heart and kidneys.
• Thermoregulation, that is, keeping body temperature steady.
• Controlling the sensations of hunger and thirst.
• Managing the circadian rhythms of the body, the natural twenty-four-hour cycles of activity.
• Governing the activity of several endocrine glands.
• Shaping human behaviour.

Beyond these, the brain is also the site where vision, hearing and speech are processed, and where memory, intelligence, emotions and thoughts arise.

Protection of the brain

Because it is so vital, the brain is very well protected. It is housed inside the bony skull, which shields it from mechanical injury. Within the skull, the brain is further wrapped by three protective membranes called the cranial meninges. Arranged from the outside inwards, these are:

• The dura mater, the tough outer layer.
• The arachnoid, a very thin middle layer.
• The pia mater, the innermost layer, which lies in direct contact with the brain tissue itself.

Major divisions of the brain …